/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.util;



import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.lang.ref.SoftReference;



/** Utility functions for stream operations. */

public class StreamUtils {



  private StreamUtils() {}



  private static final int BUF_SIZE = 8192;



  private static ThreadLocal<SoftReference<byte[]>> threadLocalBuffer = new ThreadLocal<>();



  /** Efficient converting stream to bytes. */

  public static byte[] getBytesWithoutClosing(InputStream stream) throws IOException {

    if (stream instanceof ExposedByteArrayInputStream) {

      // Fast path for the exposed version.

      return ((ExposedByteArrayInputStream) stream).readAll();

    } else if (stream instanceof ByteArrayInputStream) {

      // Fast path for ByteArrayInputStream.

      byte[] ret = new byte[stream.available()];

      stream.read(ret);

      return ret;

    }

    // Falls back to normal stream copying.

    SoftReference<byte[]> refBuffer = threadLocalBuffer.get();

    byte[] buffer = refBuffer == null ? null : refBuffer.get();

    if (buffer == null) {

      buffer = new byte[BUF_SIZE];

      threadLocalBuffer.set(new SoftReference<>(buffer));

    }

    ByteArrayOutputStream outStream = new ByteArrayOutputStream();

    while (true) {

      int r = stream.read(buffer);

      if (r == -1) {

        break;

      }

      outStream.write(buffer, 0, r);

    }

    return outStream.toByteArray();

  }

}